الملخص

Abstract In this work, several pieces of CR-39 detector were irradiated by UV radiation in order to study their physical characteristics. A UV spectrometer was utilized to read radiation coming out of the CR-39 detectors., and obtain their optical absorption. It was realized that the optical absorption wave length range was between 190-1110 nm. Near 314-316 nm at the absorption peak, a UV spectrum change was oserved in which there was an energy gap (Eg) variation which was confirmed by the Urbach equation. It was interesting to notice that the indirect inergy gap value was less than that of the direct gap value. Both direct and indirect energy gaps do increase with increasing dose of UV radiation.The number of carbon atoms (N) was calculated depending on direct and indirect energy gaps return to the equation (4).It was also observed that the excitation electron, Urbach energy (Eu), do actually decrease when UV radiation dose is increased.